From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
To: Daniel Borkmann <daniel@iogearbox.net>
Cc: netdev@vger.kernel.org, linux-sctp@vger.kernel.org,
Neil Horman <nhorman@tuxdriver.com>,
Vlad Yasevich <vyasevich@gmail.com>
Subject: Re: [PATCH net] sctp: linearize early if it's not GSO
Date: Wed, 17 Aug 2016 00:49:31 +0000 [thread overview]
Message-ID: <20160817004931.GF3110@localhost.localdomain> (raw)
In-Reply-To: <57B39AC5.7000002@iogearbox.net>
On Wed, Aug 17, 2016 at 12:59:17AM +0200, Daniel Borkmann wrote:
> On 08/17/2016 12:35 AM, Marcelo Ricardo Leitner wrote:
> > Because otherwise when crc computation is still needed it's way more
> > expensive than on a linear buffer to the point that it affects
> > performance.
> >
> > It's so expensive that netperf test gives a perf output as below:
> >
> > Overhead Shared Object Symbol
> > 69,44% [kernel] [k] gf2_matrix_square
> > 2,84% [kernel] [k] crc32_generic_combine.part.0
> > 2,78% [kernel] [k] _raw_spin_lock_bh
>
> What kernel is this, seems not net kernel?
>
> $ git grep -n gf2_matrix_square
> $ git grep -n crc32_generic_combine
> $
>
> Maybe RHEL? Did you consider backporting 6d514b4e7737 et al?
Damn, correct. I'll post a v2 later with a proper changelog.
No I hadn't considered backporting that commit.
Now from a different environment, upstream kernel, without the patch, using
mlx4 and perf record -a -- sleep 5 during netperf (Xeon E5-2690 v3, 24 cpus):
Overhead Command Shared Object Symbol
16,85% netserver [kernel.vmlinux] [k] crc32_generic_shift
3,46% swapper [kernel.vmlinux] [k] intel_idle
2,00% netserver [kernel.vmlinux] [k] __pskb_pull_tail
1,73% netserver [kernel.vmlinux] [k] copy_user_enhanced_fast_string
1,72% swapper [kernel.vmlinux] [k] crc32_generic_shift
1,64% swapper [kernel.vmlinux] [k] poll_idle
1,59% netserver [kernel.vmlinux] [k] memcpy_erms
1,57% netserver [kernel.vmlinux] [k] fib_table_lookup
1,47% netserver [kernel.vmlinux] [k] _raw_spin_lock
1,37% netserver [kernel.vmlinux] [k] __slab_free
1,32% netserver [sctp] [k] sctp_packet_transmit
1,18% netserver [kernel.vmlinux] [k] skb_copy_datagram_iter
With the patch:
Overhead Command Shared Object Symbol
4,71% swapper [kernel.vmlinux] [k] intel_idle
2,11% netserver [kernel.vmlinux] [k] copy_user_enhanced_fast_string
1,45% netserver [kernel.vmlinux] [k] memcpy_erms
1,29% swapper [kernel.vmlinux] [k] memcpy_erms
1,28% netserver [kernel.vmlinux] [k] fib_table_lookup
1,27% netserver [kernel.vmlinux] [k] __slab_free
1,27% swapper [kernel.vmlinux] [k] fib_table_lookup
1,26% netserver [kernel.vmlinux] [k] kmem_cache_free
1,14% netserver [kernel.vmlinux] [k] _raw_spin_lock
1,07% netserver [kernel.vmlinux] [k] __pskb_pull_tail
1,06% netserver [kernel.vmlinux] [k] skb_copy_datagram_iter
1,04% netserver [sctp] [k] sctp_packet_transmit
1,04% swapper [kernel.vmlinux] [k] __pskb_pull_tail
1,01% swapper [mlx4_en] [k] mlx4_en_process_rx_cq
0,99% swapper [kernel.vmlinux] [k] native_queued_spin_lock_slowpath
0,96% swapper [kernel.vmlinux] [k] _raw_spin_lock
0,89% swapper [sctp] [k] sctp_packet_transmit
Without the patch:
# netperf -H 192.168.10.1 -l 10 -t SCTP_STREAM -cC -- -m 12000
SCTP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.10.1 () port 0 AF_INET
Recv Send Send Utilization Service Demand
Socket Socket Message Elapsed Send Recv Send Recv
Size Size Size Time Throughput local remote local remote
bytes bytes bytes secs. 10^6bits/s % S % S us/KB us/KB
212992 212992 12000 10.00 2896.13 3.34 3.88 2.267 2.635
With the patch:
# netperf -H 192.168.10.1 -l 10 -t SCTP_STREAM -cC -- -m 12000
SCTP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.10.1 () port 0 AF_INET
Recv Send Send Utilization Service Demand
Socket Socket Message Elapsed Send Recv Send Recv
Size Size Size Time Throughput local remote local remote
bytes bytes bytes secs. 10^6bits/s % S % S us/KB us/KB
212992 212992 12000 10.00 3444.89 3.88 3.02 2.216 1.721
And without the patch netperf fluctuates more as there are more packet
drops and netserver is constantly at 100% cpu usage.
Thanks,
Marcelo
prev parent reply other threads:[~2016-08-17 0:49 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-16 22:35 [PATCH net] sctp: linearize early if it's not GSO Marcelo Ricardo Leitner
2016-08-16 22:59 ` Daniel Borkmann
2016-08-17 0:49 ` Marcelo Ricardo Leitner [this message]
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